information_schema.columns table incorrectly parsed for 5.5 versions

[guriandoro]

In mysql 5.5 versions, the information_schema.columns doesn't have the DATETIME_PRECISION column, so there were errors when trying to run against 5.5:

ERRO[0000] Cannot get table fields: sql: expected 19 destination arguments in Scan, not 20

The following function should be changed (PR in progress for this):

https://github.com/Percona-Lab/mysql_random_data_load/blob/master/tableparser/tableparser.go#L213

[svetasmirnova]

The same error happens when I try to load data into MariaDB 10.2.27 instance. I believe it will fail for other versions of MariaDB too.